Rating\Rating::_getNewRatings PHP Method

    protected function _getNewRatings($ratingA, $ratingB, $expectedA, $expectedB, $scoreA, $scoreB)
    {
        $newRatingA = $ratingA + self::KFACTOR * ($scoreA - $expectedA);
        $newRatingB = $ratingB + self::KFACTOR * ($scoreB - $expectedB);
        return array('a' => $newRatingA, 'b' => $newRatingB);
    }